From some simple testing in portal_types aliases:
rss-1 => @@rss-1
works!

CMFCore has:

if IActionProvider.isImplementedBy(provider):
    actions.extend( provider.listActionInfos(object=object) )

Deep in the magic, at

    def listFilteredActionsFor(self, object=None):

I propose having a IActionProvider, maybe on portal_syndication which looks up the canonical feeds on an object and exposes them to CMFCore when queried.